code: def message(self, x_j, norm):
      return norm.view(-1, 1) * x_j
  
file_path: pytorch_geometric/test/nn/conv/test_create_gnn.py
imports: import torch
  from torch_geometric.nn import MessagePassing
  from torch_geometric.utils import add_self_loops, degree
label_desc: Use image node_id 3 for calling the GCNConv obj's underlying member method code with example usage: obj.message(x_j, norm) and returns: unknown